Oxygen is a necessary element in the life of human. When our bodies lack oxygen, some problems occur in the functions of bodies, sometimes causing various diseases.
For example, headache, vomiting, breathing increase, pulse rate increase, fatigue, dizziness or something occurs. In worse case, convulsion and athymia occurs, and it causes a death. Since the immunity system of a human body is destroyed, the human body can be easily infected with bacteria or viruses, thus consequently causing various diseases.
Water existing in the nature has a certain amount of oxygen in a dissolved form. The dissolved saturation level might vary depending on the temperature of water; however the dissolved oxygen concentration under a room temperature atmosphere is about 6 ppm to 8 ppm. The dissolved oxygen in water necessarily exists in terms of plants and life as a prerequisite essential. When dissolved oxygen is less than 2 ppm, both plants and life die.
For this reason, there is a lot of interests in oxygen water known to have a lot of contents of oxygen as compared with a common water.
The dissolved oxygen contained in oxygen water is absorbed into blood by way of stomach and is circulated to each cell tissue by a blood circulation operation and is used as an energy needed for metabolism. The dissolved oxygen taken by drinking oxygen water is absorbed into each cell tissue more than 10 times faster than the oxygen which is taken by way of lungs, which might has a little difference depending on the partial pressure of oxygen in a human body. As the concentration of oxygen in oxygen water is higher, the amount of oxygen to be absorbed into a human body much more increases.
For example, the concentration of oxygen in the air in a forest which provides a woods bathing is 1% or 2% higher than 21% of a typical oxygen concentration; however the freshness that a human body feels is great. So, it is obvious that the effects by oxygen water might be great, which might not be compared with the effects by woods bathing.
It is needed to dissolve oxygen into water so as to manufacture oxygen water having more oxygen contents than a typical water. As a typical way of dissolving oxygen into water, oxygen is spread into water in a form of fog by using air stone generally used in an aquarium; however it is almost hard to quickly dissolve and produce oxygen water with a high concentration due to a physical limit.
Alternatively, there is a way of dissolving more oxygen into water by filling oxygen into a tank with water at a high pressure based on the Henry's law that the mass of the gas dissolved in liquid is in proportion to the pressure of gas.
However, it is impossible to dissolve the oxygen with a concentration higher than a certain level, and it takes long to dissolve oxygen.